Exhaust arrangement in a rotary-piston internal combustion engine

ABSTRACT

In a rotary-piston, internal combustion engine in which pistons rotate about the axis of a cylindrical casing in circumferentially consecutive relationship in sealing engagement with the casing and move angularly relative to each other in such a manner that each pair of circumferentially consecutive pistons defines a combustion chamber of the engine which expands and contracts during rotation, the casing is formed with an intake port for admitting a fuel mixture to the expanding chambers and with an exhaust port and an auxiliary port juxtaposed circumferentially in the direction of piston movement for releasing the spent fuel mixture as combustion gases from the contracting chambers. A conduit extends from the exhaust port outward of the casing and terminates in a tapering, open nozzle. Another conduit extends from the auxiliary port and has a throat portion spacedly enveloping the nozzle so as to form a jet pump or ejector pump therewith, the pressure of the combustion gas discharged from the nozzle drawing additional gas at lower pressure from the combustion compartment.

United States Patent [191] Sabet EXHAUST ARRANGEMENT IN A ROTARY-PISTON INTERNAL COMBUSTION ENGINE [76] Inventor: Huschang Sabet,

Eduard-Pfeiffer-Strasse 67, Stuttgart, Germany [22] Filed: Aug. 30, I972 [21] Appl. No.: 284,897-

Related US. Application Data [63] Continuation-impart of Ser. No. 137,870, April 27,

1970, Pat. No. 3,736,080.

[30] Foreign Application Priority Data Oct. 19,1971 Germany P 21 51 988.0

[52] US. CL... 123/813, 123/8.47

[51] Int. Cl F02b 53/04 [58] Field of Search 123/8.47, 8.01, 8.13

[56] References Cited UNITED STATES PATENTS 1,255,403 2/1918 Gardner 123/847 X 1,298,839 4/1919 Weed 123/8.47

FOREIGN PATENTS OR APPLICATIONS 630,461 10/1949 Great Britain 123/8.47 947,812 1/1964 Great Britain l23/8.47

[ Dec. 4, 1973 Primary Examiner-Clarence R. Gordon Attorney-Kurt Kelman [57] ABSTRACT In a rotary-piston, internal combustion engine in which pistons rotate about the axis of a cylindrical casing in circumferentially consecutive relationship in sealing engagement with the casing and move angularly relative to each other in such a manner that each pair of circumferentially consecutive pistons defines a combustion chamber of the engine which expands and contracts during rotation, the casing is formed with an intake port for admitting a fuel mixture to the expanding chambers and with an exhaust port and an auxili- 5 Claims, 2 Drawing Figures PATENTEUBEB 4 m5 sum 10; 2

Fig. 1'

" PATENTEDBEC 4 1975 SHEET 2 f 1 EXHAUST ARRANGEMENT IN A ROTARY-PISTON INTERNAL COMBUSTION ENGINE This application is a continuation-in-part of the copending applications Ser. No. l'37,870,.filed on Apr. 27, 1971, now US. Pat. No. 3,736,080.

In the afore-mentioned application, there-has been disclosed a rotary-piston, internal-combustion engine in which a fluid combustion mixture .is exploded in combustion chambers between pistons which rotate about the axis of a'casing ofcircular cross section while sealinglyengaging the .casing in circumferentially consecutive relationship, and the .chambers are expanded and contracted by relative angular movement of the two pistons bounding each chamber. Intake and exhaust ports communicate with the chambers during rotation of the pistons to supply the combustion mixture to the expanding chambers and .to'release spent combustion gases from the' contractingchambers when the chambers communicate with the respective ports.

As is also being disclosed in the simultaneously filed application, Ser. No. 284,896 entitled Intake and'Exhaust Arrangement for Rotary-Piston, lntemal- Combustion Engine, the pistons are fixedly connected in two sets of which one rotates at uniform speed whereas the rotary speed of the other set varies cyclically to produce the relative angularmovement of the two sets and the expansion and contraction of the chambers, each chamber being bounded circumferentially by'respective faces of pistons of each set. Under certain conditions,.it is advantageous to havetwo circumferentially closely juxtaposed'ports, each having'a circumferential width smaller than the corresponding dimension of any piston, for releasing combustion gases from the casing.

ferred to above can be combined to advantage with a jet pump or ejector pump operated by the combustion gases initially released to withdraw residual combustion gases from the engine casing.

For the convenience of description, the port first communicating with a combustion chamber during operation of the engine-will hereinafter be'refe'rred to as the exhaust port, while the second port spaced circumferentially in the engine casing from the last-mentioned exhaust port in the direction of rotary piston movement will be referred to as the auxiliary .port. The spacing of the two ports is smaller than the circumferential width of the exhaust port and respective conduits extend from the two ports in a direction outward of the casing. One of the conduits has a throat portion, and the other conduit terminates in an open nozzle portion located in the throat portion and constituting therewith an ejector or jet pump.

Other features and many of the attendant advantages of this invention will readily become apparent as the invention is better understood by reference to the following detailed description of a preferred embodiment when considered in connection with the appended drawing in which:

FIG. 1 shows an exhaust arrangement of the inventionin fragmentary, radial section throughthe engine rangement of the simultaneously filed application recasing on the line I I in'FIG. 2; and

' FIG. 2 is a developed, fragmentary view of the inner face of the engine casing partly shown in FIG. 1.

Referring now to the drawing in detail, and initially to FIG. 1, there is shown-only as much of the engine disclosed in the two afore-mentioned copending applications as is needed for an understanding of the'invention, the principal operating parts of the engine being respresented only by a portion of the cylindrical casing wall l. A narrow partition 2, which is an integral portion of the casing, circumferentially separates an exhaust port 3 and an auxiliary port 4 which extend through the casing 1 in a common radial plane, and of which each has a circumferential width several times the corresponding dimension of the partition 2.

A straight cylindrical tube 5 connected to the casing l by a gastight weld leads radially outward of the casing from the exhaust port 2. It terminates in a tapering, open nozzle 6. Another tube 7 having the approximate shape of a skewed frustum of a cone is sealed to the outer face of the casing 1 so as to enclose the orifice of theauxiliary port 4 and spacedly to envelop the tube 5. The tube 7 tapers in a direction outward of the casing 1 toward a throat portion of 8 of circular cross section about an axis which coincides with that of the nozzle 6. The throat portion 8 axially converges and then diverges and is dimensioned to define an annular gap about the common axis with the nozzle 6. Two restricted apertures 9 in the diverging portion of the throat 8 connect the interior of the latter contiguously adjacent the open end of the nozzle 6 with the ambient aperture. A cylindrical chamber 10, coaxial with the throat 8 and the nozzle 6 extends from the throat 8 away from the ports 3, 4. The end of the chamber 10 not seen in FIG. 1 communicates with the atmosphere. An ignition element 11, electrically headed or of catalytic platinum group metal, is centered in the cross section of the chamber 10 and supported on a spider 11' so as to offer minimal r'esistance' to the discharged gases. A blanket 12 of thermal insulation material covers the outer surface of the tube 7 and of the throat 8.

As is evident from joint consideration of FIGS. 1 and 2, the exhaust port 3 and the auxiliary port 4 are identical rectangular openings in the casing wall 1 which are circumferentially aligned in a common radial plane while the intake port 13 is located in a second radial plane axially spaced in the casing wall 1 from the plane of the ports 3, 4, and is circumferentially offset from the auxiliary port 4 in the direction of rotary movement of the non-illustrated pistons in the casing I, the movement being counterclockwise, as viewed in FIG. 1, and from the right to the left as viewed in FIG. 2. A narrow axial slot 14 in the casing wall 1 is axially aligned with the portion of the auxiliary port 4 farthest from the exhaust port 3 and circumferentially aligned with the intake port 13. Its orifice in the outer face of the casing wall 1 freely communicates with theambient atmosphere outside the tube 7.

The pistons in the casing 1 which alternatingly block and clear the ports 3,4,13 and the slot 14 during their movement about the axis of the casing wall 1 have been shown in detail in the simultaneously filed application referred to above. A chamber containing hot gases of combustion and circumferentially bounded by two pistons contracts while communicating with the exhaust port 3. The hot compressed gases are discharged through the nozzle 6, thereby producing a subatmospheric pressure in the tube 7 between the auxiliary port 4 and the throat 8. Approximately simultaneously with the forming of a vacuum in the tube 7, the auxiliary port 4 is cleared by the piston leading the contracting combustion chamber, and the discharge from the chamber of the residual gases of reduced pressure is enhanced by the suction effect of the jet pump 6,8. A small amount of atmospheric air is drawn into the combustion chamber through the slot 4 to scavenge the chamber, and is partly mixed with the discharged gas. The gases are kept hot in the ejection pump 6,8 by the insulating blanket 12, and the normal operating temperature of the tubes 5,7, particularly that of the pipe '5, is not significantly different from that of the combustion gases for high efficiency of the pump.

Additional air is drawn into the throat 8 by the jet or ejection pump 6,8 through the apertures 9, and the slot 14 and apertures 9 are dimensioned to provide secondary air of combustion for residual fuel and carbon monoxide in the combustion gases entering the chamber 10. The combustible mixture is ignited by the ignition element 11 to improve the environmental properties of the exhaust gases in a manner known in itself. Obvious, any other known catalyst system or afterburner arrangement may be provided in the chamber 10.

Only a single set of ports 3,4,13 and a single ejection pump arrangement have been shown in the drawing,

but it will be appreciated that the device illustrated and described will be repeated-around the circumference of the casing wall 1 as often as the specific number and operation of the non-illustrated pistons requires, and that the several chambers may be linked to a common exhaust pipe or to plural exhaust pipes in a manner conventional in automotive engineering. The chamber 10 alone or in combination with an associated exhaust pipe causes the combustion gases to be discharged at a substantially uniform rate although they leave the ports 3,4 intermittently.

If the effective circumferential width of the nonillustrated pistons is made small enough, the ports 3,4 may communicate respectively with two circumferentially consecutive combustion chambers of the engine in such a manner that the exhaust port 3 and the nozzle 6 communicate with a combustion chamber in which the prevailing pressure is higher than in the chamber communicating with the auxiliary port 4, and such an arrangement is most effective and preferred. It requires the circumferential piston face to be of smaller angular width relative to the casing axis than the combined angular width of the ports 3,4 and the partition 2. In such an arrangement, the slot 14 may be omitted because scavenging of the combustion chamber is not necessary when strong suction is developed at the ejection pump 6,8 for a relatively long period.

It should be understood, of course, that the foregoing disclosure relates only to a preferred embodiment of the invention, and that it is intended to cover all changes and modifications of the example of the invention chosen herein for the purpose of the disclosure which do not constitute departures from the spirit and scope of the appended claims.

What is claimed is: v

1. An exhaust arrangement in an internalcombustion, rotary-piston engine having a cylindrical casing including a wall of circular cross section perpendicular to an axis of said wall, said wall being formed with an intake port for admitting a fluid to said casing and with an exhaust port for releasing fluid from said casing, the improvement which comprises:

a. said intake port and said exhaust port being offset from each other in the direction of said axis, and circumferentially relative to said axis,

b. said wall being formed with an auxiliary port circumferentially interposed between-said intake and exhaust ports, said auxiliary port extending in a common plane perpendicular to said axis with said exhaust port, the circumferential spacing of said auxiliary port from said intake port and from said exhaust port being substantially smaller than the circumferential width of any one of said ports,

. a first conduit elongated in a radially outward direction and communicating with said exhaust port, said conduit having a terminal nozzle portion of reduced cross section remote from said wall,

d. a second conduit communicating with said auxiliary port and having a throat portion of reduced cross section spacedly enveloping said nozzle portion, said second conduit flaring in a direction radially outward of said throat portion, whereby said conduits jointly constitute an ejector pump.

2. In an arrangement as set forth in claim 1, said second conduit having a chamber portion of greater cross section than said throat portion and extending from said throat portion in a direction outward of said cas ing, and igniting means for igniting a combustible fluid in said chamber portion;

3. In an arrangement as set forth in claim 2, said throat portion being formed with a restricted aperture therethrough, said aperture communicating with ambient atmosphere.

4. In an arrangement as set forth in claim 1, said casing being formed with an aperture therethrough, said aperture being circumferentially coextensive with said auxiliary port, having a flow section smaller than said auxiliary port, and communicating with the ambient atmosphere.

5. An arrangement as set forth in claim 4, said aperture being axially coextensive with said intake port. 

1. An exhaust arrangement in an internal-combustion, rotarypiston engine having a cylindrical casing including a wall of circular cross section perpeNdicular to an axis of said wall, said wall being formed with an intake port for admitting a fluid to said casing and with an exhaust port for releasing fluid from said casing, the improvement which comprises: a. said intake port and said exhaust port being offset from each other in the direction of said axis, and circumferentially relative to said axis, b. said wall being formed with an auxiliary port circumferentially interposed between said intake and exhaust ports, said auxiliary port extending in a common plane perpendicular to said axis with said exhaust port, the circumferential spacing of said auxiliary port from said intake port and from said exhaust port being substantially smaller than the circumferential width of any one of said ports, c. a first conduit elongated in a radially outward direction and communicating with said exhaust port, said conduit having a terminal nozzle portion of reduced cross section remote from said wall, d. a second conduit communicating with said auxiliary port and having a throat portion of reduced cross section spacedly enveloping said nozzle portion, said second conduit flaring in a direction radially outward of said throat portion, whereby said conduits jointly constitute an ejector pump.
 2. In an arrangement as set forth in claim 1, said second conduit having a chamber portion of greater cross section than said throat portion and extending from said throat portion in a direction outward of said casing, and igniting means for igniting a combustible fluid in said chamber portion.
 3. In an arrangement as set forth in claim 2, said throat portion being formed with a restricted aperture therethrough, said aperture communicating with ambient atmosphere.
 4. In an arrangement as set forth in claim 1, said casing being formed with an aperture therethrough, said aperture being circumferentially coextensive with said auxiliary port, having a flow section smaller than said auxiliary port, and communicating with the ambient atmosphere.
 5. An arrangement as set forth in claim 4, said aperture being axially coextensive with said intake port. 